OEM EFI computers

[David Cooley]

>
>    I looked at the GM computer system very extensively. (1992 5.7 TBI moel)
>That computer uses a 68hc11FN. Nice chip. All of the code resides on the
>27256 in the calpack. Thats a 64k byte rom, and the cpu only has a 64k byte
>adress space, so I am assuming that ALL of the code is on the calpack. Oh,
>yeah, that version of the '11 has programable chip selects too. Anyway,  I
>doubt that GM bothered with programing the on chip mask ROM when they had
>that big EPROM to use.  I am wondering if the GNX really used the 6801, or if
>it was really a 6811. Anyone know this for sure? I would guess that they used
>the '11 on the GNX, because its the first production car that GM ever
>implimented SEFI on. The coding of a 6801 would be very dificult as compared
>with the code required for the '11. The timer section of the '11 almost lends
>itself to SEFI.  Oh, yeah, Can I get a copy of the GNX code? Is it
>disasembled? Is it comented (yeah, right!) ?
>
>    ---Lou 
>
>

Lou,
The GN from 84 thru 87 and the GNX all used the same ECM, all 6801 based,
and all SEFI.  The chip of the GNX was the same code, but tables for top
speed fuel cut and boost were modified.  I'll send you a copy of the
disassembled prom, and the binary of the chip (stock 87GN).  The disassembly
shows all the program code, but only the address range for the tables... The
binary will give you the table structure.
Thanks,
Dave
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David Cooley  AKA N5XMT                                 (919) 319-2734 Office
cooldave at nando.net                                      (919) 319-2896 FAX
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